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Discussion Starter #1
73 W100 360. no upgrades to the charging system (yet)

Im starting to work on some upgrades to this truck. I started with replacing the instrument cluster VR. as seen here:
http://www.allpar.com/history/mopar/electrical2.html

I was testing the output with a multimeter. i found that the input had 17v. the 5v output was not working.

Green = battery input (currently 17v)
yellow = ground
brown = 5v output (currently 2.2v and fluctates)

1. 17v is too high. im trying to fix that.
2. 5v output is not 5v. ordered new VRs hopefully to fix this


did I get the wiring correct? do you see anything that is off?
 

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I did this upgrade three years ago and everything worked fine. To answer your question, yes you do have it wired wrong. your '12 volt' supply wire is fine but you have the ground wire and '5 volt' output wires in the wrong spot. Swap those wires on the cluster board and you will be fine. Move the ground side of the capacitor along with the ground wire also. As a double check, re-read the allpar write up and test again with your multimeter.
 

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Discussion Starter #3 (Edited)
I did this upgrade three years ago and everything worked fine. To answer your question, yes you do have it wired wrong. your '12 volt' supply wire is fine but you have the ground wire and '5 volt' output wires in the wrong spot. Swap those wires on the cluster board and you will be fine. Move the ground side of the capacitor along with the ground wire also. As a double check, re-read the allpar write up and test again with your multimeter.
Will do. Thanks for the note. I will post the results.

the allpar instructions say to look for the ground screws. it appears that the yellow is already on the copper circuit that has the ground nuts.
 

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Discussion Starter #4
ok so I swapped the wires. better results but still not fixed.

green = 17v+ (was 18.6v today when tested)
5v = reads 6.3v now.

I wonder if I cooked the regulator because it was wired wrong. I have ordered a few more VRs and capacitors.

guages dont appear to work. the regulator is the first thing ive changed/tested so im not worried about the guages yet. Im mainly concerned with the 18v output.
 

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I cannot say you did or did not fry the vr. I can say that while the allpar write up said to look for the ground screws, the GROUND SCREWS will not be connected to any of the copper circuit runs. What you took for ground screws/nuts were actually the three gauge posts needing the 5V supply from the regulator.

Do you have a wiring diagram? If not, then try to find one as it will help in understanding how these circuits work. If you pull the round wireing connector off of the circuit board you will see the alphabetical listing for identifying the posts on the bottom of the connector. Post C will be your 12V supply to the regulator and lights in the cluster. Post D will be the ground.

As far as the actual voltage supplied to the regulator, The regulator should be able to handle what you have stated. If you used the recommended VR then it should be rated as 35V max input. ( I say this because that is what I used for my setup ) The output will be 5V.

I do know that when you first start the truck, the vehicles voltage regulator will show a higher output reading than 12V. This reading will eventually settle down to about 14 - 15 volts while the truck is running. It will also fluctuate as you use various electrical components.

Build another VR for your instrument cluster since you have more parts and try it again. This upgrade will give you more solid gauge readings.
 

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Discussion Starter #6
@K-Ray thanks for the help. I dont have a diagram. I will look one up. Thanks to you it is working better. Im still concerned about the high voltage. but im going to be upgrading the alternator and putting an HEI ignition on it here soon. Ill see how it it works then.
 
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